how about Kuala lumpur ? you can go shopping at 雙子塔 & starhill mall. And bring the kids going to 雲頂高原. Some games is suitable for young children although it's rather old.
I took my 3-year-old kid to kuala lumpur last year. There is an indoor amusement park in the Times Square Shopping Centre. One part is for kid and one is for adults. We spent a half day there and my son really enjoyed it. We also went to the Sunway Lagoon one day playing water and there is also some rides on the other side. Quite good!